Updated implementation of cached property

Cached value of properties are stored
in instance's '__dict__'.

breadability/utils.py

@@ -4,17 +4,16 @@
 def cached_property(getter):
     """
     Decorator that converts a method into memoized property.
-    The decorator will work as expected only for immutable properties.
+    The decorator works as expected only for classes with
+    attribute '__dict__' and immutable properties.
     """
     def decorator(self):
-        if not hasattr(self, "__cached_property_data"):
-            self.__cached_property_data = {}
+        key = "_cached_property_" + getter.__name__
 
-        key = getter.__name__
-        if key not in self.__cached_property_data:
-            self.__cached_property_data[key] = getter(self)
+        if not hasattr(self, key):
+            setattr(self, key, getter(self))
 
-        return self.__cached_property_data[key]
+        return getattr(self, key)
 
     decorator.__name__ = getter.__name__
     decorator.__module__ = getter.__module__